1. Field of the Invention
This invention relates to an animal litter to which has been applied an odor-inhibiting agent which is believed to act by antimicrobial action, acidity, controlling urease, or a combination of these mechanisms to control odor after the litter is used by the animal. The preferred odor control animal litter is a clay-based, particulate substrate to which has been applied a liquid carrier containing a boron-containing material at a critical level of at least 0.06% equivalent boron.
2. Brief Description of the Prior Art Because of the growing number of domestic animals used as house pets, there is a need for litters so that animals may micturate, void or otherwise eliminate liquid or solid waste indoors in a controlled location However, inevitably, waste build-up leads to malodor production.
As one solution to this problem, Eichenauer, U.S. Pat. No. 4,628,863 suggests a disposable cat litter box which is easily collapsible and can be disposed of in a very compact form. However, this approach, intended for consumer convenience, does not overcome the problem of malodor production.
Kuceski et al, U.S. Pat. No. 3,059,615, Sawyer et al, U.S. Pat. No. 3,029,783, Currey, U.S. Pat No. 4,306,516 and Wortham, U.S. Pat. No. 3,892,846, all suggest the use of fairly strong inorganic or organic acids to treat litters in an effort to control ammonia formation in litters. In each instance, it appears that these acids are essentially used to neutralize ammonia to form an odorless salt, e.g., sulfuric acid combining with ammonia to produce ammonium sulfate.
Still others have sought to decrease odors in litters by improving the absorption rate of the litter itself. E.g., Fry et al, U.S. Pat. No. 3,923,005. Yet another attempt to overcome the problem of odor formation is Colborn et al, U.S. Pat. No. 4,407,231, which, unlike other prior art attempts which merely used a superficial treatment of fragrance, teaches pressure-sensitive encapsulated fragrance particles which frangibilize with the weight of the animal.
Also, two references disclose deodorization of sewage by direct, topical application of, respectively, a trichloroisocyanuric acid (Gould, U.S. Pat. No. 4,054,518) and alkylbenzene sulfonic acid (Ohtsuka, Japan Pat. No. 75-05,538), in both of which cases boric acid is included as a additive in relatively small amounts. Gould apparently uses boric acid as a dispersing agent for the trichloroisocyanuric acid. Ohtsuka, on the other hand, uses the alkylbenzene-sulfonic acid for its emulsifying and foaming properties. Also, Clark et al, U.S. Pat. No. 3,352,792, discloses a deodorant for animal litter containing a dry mixture of magnesium carbonate and borax.
Further, Christianson, U.S. Pat. No. 4,263,873, discloses cellulose pellets impregnated with a pheromone to induce animals to micturate or void in the litter which has a preferred pH of 4-4.5. Christianson further suggests, but does not exemplify, the use of boric acid or borax as odor control materials.
However, none of the foregoing art teaches, discloses or suggests the use of a clay-based litter which has been treated with a urease inhibition/odor control agent comprising a liquid carrier containing a boron-based material at a critical equivalent boron level of at least 0.06%.